Grant Cohn: Five 49ers who have a lot to prove against Rams

San Francisco 49ers running back Matt Breida (22) runs against the Jacksonville Jaguars in Santa Clara, Sunday, Dec. 24, 2017. (AP Photo/Tony Avelar)


Forget the Rams.

Sunday’s game means nothing to them. They’re going to the playoffs and resting their stars against the 49ers. Jared Goff, Todd Gurley, Aaron Donald, Andrew Whitworth and John Sullivan won’t play. They don’t have anything to play for.

This game is all about the 49ers.

The Niners want to win, no matter what the Rams want to do. A win would give the Niners momentum heading into 2018. A loss to the Rams B-team would be devastating.

Each player on the 49ers is playing for his career this Sunday, trying to prove he belongs with the 49ers next season and into the future.

These are the five players with the most to prove.

1. WR Kendrick Bourne.

Soon, the 49ers will need a replacement for wide receiver Pierre Garcon, who’s 31 and recovering from a fractured neck.

Garcon is a big, tough possession receiver. The only other receiver like him currently on the roster is rookie Kendrick Bourne.

Bourne is 6-foot-1 and 203 pounds. The 49ers signed him as an undrafted free agent, and he made the 53-man roster after training camp. Two weeks ago, he caught a 54-yard pass during the fourth quarter of a 25-23 win against the Tennessee Titans.

Was that a freak occurrence, or something he can build on? Is he good enough to be Garcon’s heir apparent, or do the 49ers still have to find that player?

Bourne’s performance against the Rams could help answer those questions. If he plays well, the 49ers may not spend a high draft pick on a wide receiver in April.

2. RB Matt Breida.

We need to know if Breida can be the starting running back next season.

The current starter, Carlos Hyde, is scheduled to be a free agent and isn’t playing well. He’s averaging 3.8 yards per carry — the lowest number of his career.

Last week, he carried the ball 21 times and gained only 54 yards (2.57 yards per carry) against the Jacksonville Jaguars. Meanwhile, Breida rushed for 74 yards on 11 carries — 6.73 yards per carry.

On Tuesday, I asked Kyle Shanahan if Breida is good enough to be a starter.

“Yeah, I think Breida has the ability to,” Shanahan said.

But does he have the durability? Can he carry a running game? He weighs only 190 pounds — small for a running back — and he never has carried the ball more than 12 times in an NFL game.

If the Niners give Breida a big workload against the Rams, they’re auditioning him for the starting role. If they give him another modest workload, that could mean they want to re-sign Hyde, or find someone other than Breida to replace Hyde next season.

3. DL Aaron Lynch.

Lynch did less for himself and the franchise this season than anybody on the team.

He could have been the edge-rusher the 49ers were missing opposite Elvis Dumervil. Instead, Lynch reported to the offseason training program 30 pounds overweight, injured his calf Week 6 and played in only seven games this season. He has one sack.

When he was young, he had the skillset to be a quality pass rusher. He recorded 12.5 sacks his first two seasons. Now, he just makes silly mistakes. He committed two offside penalties, one neutral zone infraction and a roughing-the-passer-penalty this season.

I want to see if he plays like he cares against the Rams. He’s only 24 years old. If he could show discipline and enthusiasm on Sunday, he could turn his career around.

4. DL Solomon Thomas.

The Niners drafted Thomas with the third pick this year expecting he’d be a franchise cornerstone. So far, he isn’t one.

He’s solid against the run, but the NFL is a passing league. A franchise-cornerstone defensive lineman has to be a good pass rusher.

And as a pass rusher, Thomas is a journeyman. He has only three sacks this season. Last week he recorded a sack, but it was a garbage sack. He fell on his face, reached forward and tripped Blake Bortles as Bortles scrambled out of the pocket.

Thomas almost always rushes directly into the offensive lineman’s chest — a major mistake. Every defensive line coach teaches his players to rush around an offensive lineman, to work an edge of him.

I asked Thomas this week why he struggles working edges. He said, “It’s harder than it looks.”

It really isn’t. The key is not to run directly into the blockers. Duh.

Thomas will face the Rams backup left tackle on Sunday. Thomas needs to beat this guy. Otherwise, Thomas might be a bust.

5. QB Jimmy Garoppolo

If Garoppolo lays an egg on Sunday, people may start to wonder about him.

They’ll ask how meaningful his wins really were, and how good he really is if he couldn’t even beat the Rams backups.

I expect Garoppolo will play well on Sunday. He needs to.

Needs to continue to show improvement. Needs to continue to convert third downs. Needs to throw more touchdown passes and fewer interceptions. In four starts with the 49ers, he has thrown four TD passes and three picks. He needs to improve that ratio.

No one has more pressure to perform this Sunday than Garoppolo, even if the Rams have no pressure at all.

Grant Cohn covers the 49ers for The Santa Rosa Press Democrat and You can reach him at